mac80211: round station cleanup timer

The station cleanup timer runs every ten seconds, the exact
timing is not relevant at all so it can well run together with
other things to save power.
Signed-off-by: Johannes Berg <johannes@sipsolutions.net>
Signed-off-by: John W. Linville <linville@tuxdriver.com>

net/mac80211/sta_info.c

@@ -14,6 +14,7 @@
 #include <linux/slab.h>
 #include <linux/skbuff.h>
 #include <linux/if_arp.h>
+#include <linux/timer.h>
 
 #include <net/mac80211.h>
 #include "ieee80211_i.h"
@@ -306,7 +307,8 @@ static void sta_info_cleanup(unsigned long data)
 	}
 	read_unlock_bh(&local->sta_lock);
 
-	local->sta_cleanup.expires = jiffies + STA_INFO_CLEANUP_INTERVAL;
+	local->sta_cleanup.expires =
+		round_jiffies(jiffies + STA_INFO_CLEANUP_INTERVAL);
 	add_timer(&local->sta_cleanup);
 }
 
@@ -345,7 +347,8 @@ void sta_info_init(struct ieee80211_local *local)
 	INIT_LIST_HEAD(&local->sta_list);
 
 	init_timer(&local->sta_cleanup);
-	local->sta_cleanup.expires = jiffies + STA_INFO_CLEANUP_INTERVAL;
+	local->sta_cleanup.expires =
+		round_jiffies(jiffies + STA_INFO_CLEANUP_INTERVAL);
 	local->sta_cleanup.data = (unsigned long) local;
 	local->sta_cleanup.function = sta_info_cleanup;